When Is An Aerometric "51" Not Aerometric?

[ek-hornbeck]

When I disassemble Parker "51" aerometric pens, I find two kinds of breather tubes. Sometimes, the tube is metal (silver or stainless steel). The tube is pretty long, going pretty far into the sac, and there is a tiny little hole in the side of the tube, close to where it enters the feed.

The other kind is a short, plastic tube, which makes a little "comma" shape as it comes out the back of the feed. These do not have the tiny little hole in the side.

So, I was wondering two questions, which I was hoping someone more knowledgeable than I am about the "51" could answer.

1. I gather from the vintagepens.com site that these two kinds of breather tube are specific to the feed. On the page listing parts for sale, the entry for the Teflon tubing describes the tubing as being for "later 51s with plastic breather tubes." Does this mean that you cannot use metal breathing tubes with these later "51" models? If so, which ones? Because I have seen plastic tubes in Mark I pens. But maybe these were refurbs -- I don't know.

2. It seems to me that the plastic breathing tube is inferior, for two reasons. First, whenever I see it used in a "51," the tubing is always significantly shorter than the metal breathing tube -- it doesn't go as far back into the sac as the metal tube. This would limit the fill capacity of the pen by a lot, it seems to me -- after you have ink in the sac up to the level of the tube-end, further pressing on the squeeze bar would just push ink in and out of the sac. It's the cascading/fountaining over the end of the tube that implements the one-way "rectifier" effect that fills the pen. I suppose you could cut the tubes longer, but they aren't very straight, and perhaps they would curve over and impinge on the side of the sac? I am theorising here; what I observe is that the plastic tubes are short.

   Second, these tubes don't have the tiny little air hole in the side of the tube. But this is what makes an "aerometric filler" aerometric! It's the little inovation that lets sea-level air bleed out of a nib-up pen when cabin pressure on an airplane drops. So… what the heck? Did Parker just decide at some point to stop making their aerometric pens aerometric?

3. OK, as long as I'm asking questions, here's one more for the "51" historians: why silver? Why did Parker make the breathing tubes out of silver instead of stainless steel or some cheaper material? I mean, sure, the silver tubes are prettier, but somehow I don't think that was the reason…

E. K.

[Parker51]

The reason for Silver rather than other materials was at the time it was used highly caustic special quick drying ink was available. It turned out that Silver while thought not to be affected by that ink was. Eventually that ink was discontinued. The silver breather tubes that survived likely were not exposed to much if any of that special ink.

[pajaro]

I think they all work, long tube or shorter tube. I didn't make a habit of taking inked fountain pens on airplane flights. I always thought it unwise to tempt the heavier than air god.

[mitto]

in aero 51s the plastic breather tube if originl to the pen would have the breather hole. If an aero 51 has a plastic breather tube that doesn't have the breather hole in it, it is a replacement non-Parker breather tube that the repairer didn't bother to make a whole in it.

Edited March 9, 2017 by mitto

[Flounder]

I've seen plenty of aeros with long, rigid plastic breather tubes that include the side hole. The material has always been black.

 

The breather tube for vacs, which predate the side hole, has to be shorter to prevent the diaphragm fouling on in when the plunger is depressed.

[ek-hornbeck]

Thanks for the commentary!

 

The question remains: if I have an aerometric "51" with a short, plastic breather tube, can I replace it with one of Nishimura's steel tubes with the correct aerometric hole in the side? Do aerometric collectors come in two sizes, one for metal tubes and one for the Teflon tubing? Or are these two kinds of tube interchangeable, despite the text on the vintagepens.com web page?

 

(For purposes of this question, I'm limiting myself to Mark I aerometrics, with the lucite internals, and long-barrelled, single-jewel design.)

 

E. K.

[FarmBoy]

The collectors are the same except Demi Aero pens which are smaller. The feeds will have a different diameter hole in the back but are dimensionally the same otherwise. The metal tube is considerably smaller than the plastic tubing or the celluloid tubing used on the Vacs.

 

If you are using pigmented inks you are better off with a plastic tube and don't worry about the hoke in the side.

[ek-hornbeck]

The collectors are the same except Demi Aero pens which are smaller. The feeds will have a different diameter hole in the back but are dimensionally the same otherwise. The metal tube is considerably smaller than the plastic tubing or the celluloid tubing used on the Vacs.

 

If you are using pigmented inks you are better off with a plastic tube and don't worry about the hoke in the side.

D'oh. Sorry. I said "collector," but I meant "feed."

 

To restate my question: are there two different kinds of feeds, one for metal breather tubes and one for plastic breather tubes? It appears you are saying, "yes, they have different size holes," correct?

 

As for not worrying about the hole in the side when one is using pigmented inks: why?

 

E. K.

[mitto]

The hole has nothing to do with the kind of inks you use. What I think FB wanted to say was if you use pigmented ink you are better off using plastic tube (with or without the hole) considering the corrosion it causes to metal tubes.

 

And yes, as FB explained above, feeds with plastic tubes used in later production mk1 aero pens have wider breather holes in comparison to the ones used in earlier production feeds with sterling tubes.

[Jerome Tarshis]

We may be leaving something out of this discussion. 51 Aeros are not Aeros if they are Specials. The breather tube of the Special (later called the Standard) 51 did not have the hole meant to equalize air pressure in flight.

 

How important that hole truly is I do not pretend to know. FarmBay might know. Other enthusiasts of the Parker 51 might know.

 

I have flown with Parker 51s for many years. Admittedly not the Special, because for my first 36 years of 51 ownership I had only the one pen, which was a regular 51, and I am a creature of habit. Only once did I get more leakage than a drop or two on the hood.

 

That time I got an ink-stained shirt pocket. However, I've had the same experience, also once, after a train ride at sea level, so I don't attribute it to changing air pressure at high altitude.

 

Still, I believe the shorter breather tube of the Special was so specified as to keep the breather tube out of the ink if the pen is nib up, so I wouldn't warn anyone against flying with a Special, either. On the other hand, I don't deplore people who say "better safe than sorry" and fly only with an inked c/c pen. Or a piston-filler. Whether all those people get away with it I have no idea.

Edited March 10, 2017 by Jerome Tarshis

[mitto]

So what if you put a longer tube with a breather hole in the Special? Would that make it a truly aero regular 51?

 

I have already done that with one of my Specials that otherwise came with a lustraloy cap, gold nib and pearl jewel.

[FarmBoy]

Not convinced the hole really worked as well in practice as it did in R and D.

 

How much are you flying?

 

Is the pen upright when you are at altitude?

 

How full is the pen when you take off?

 

 

Unless you are flying upside down with the pen in your pocket...

 

 

FB

[Jerome Tarshis]

The reason for Silver rather than other materials was at the time it was used highly caustic special quick drying ink was available. It turned out that Silver while thought not to be affected by that ink was. Eventually that ink was discontinued. The silver breather tubes that survived likely were not exposed to much if any of that special ink.

 

That silver breather tube could be affected by more than Superchrome ink. In 1985 Parker gave me a virgin Parker 51 from the supply it kept for training repair technicians (that was the explanation offered me), by way of being nice to a man who was writing a magazine article about The Great Pen.

 

I never filled the pen with Superchrome ink or any controversial ink. Nevertheless, the breather tube corroded. And was in the end replaced by FarmBoy. So it wasn't just the ferocious quick-drying etc. etc. ink that could do damage.

[ek-hornbeck]

Unless you are flying upside down with the pen in your pocket...

 

Don't know why people rave about the "51" being so fabulous. It does not handle the inverted-flight issue at all.

 

E. K.

[ek-hornbeck]

if you use pigmented ink you are better off using plastic tube (with or without the hole) considering the corrosion it causes to metal tubes.

 

I've heard that ferrotannic inks and some Noodler's inks can be tough on pens (e.g., Baystate Blue). I know from personal experience that nano-pigment inks can clog pens more quickly than older, aniline-dye based inks. But I've never heard that nano-pigment inks are corrosive.

 

When I say "nano-pigment inks," I'm talking about inks such as R&K Dokumentus, De Atramentis Document ink, Montblanc Permanent Blue, Platinum's pigmented inks, and Sailor's sei-boku and kiwa-guro inks.

 

E. K.

[mitto]

Yes, they clog. And the clogging then cause corrosion of pen parts and especially of the sterling tube in a P51.

 

 

http://gregminuskin.com/?p=2426

Edited March 10, 2017 by mitto

[pajaro]

Is there any significance to this question as to whether some 51s are or are not aerometric? Do some of these pens fill and write more poorly because of the varying lengths of the tube?

[ek-hornbeck]

Is there any significance to this question as to whether some 51s are or are not aerometric? Do some of these pens fill and write more poorly because of the varying lengths of the tube?

 

I would answer the question ("When is an aerometric '51' not aerometric?") as follows.

 

An aerometric filling system is more than simply a squeeze-filling system. It is specifically a squeeze-filling system that has a breather tube, and that breather tube has a tiny hole pierced in its side close to the feed/nib/front end of the pen. The name "aerometric" is a reference to the fact that the system is designed to permit the pen to go through changes in the ambient air pressure without ejecting ink out of the nib into the inner cap. Parker's design achieves this by means of that little hole pierced in the side.

 

If you just stick a length of PTFE tubing into the back of the feed, to function as a breather tube and to act as a one-way "rectifier" gate on the squeeze filling system, you have nothing in the system to act as an "aerometric" pressure-adjustment mechanism. If you have enough ink in your pen so that the breather tube extends into the ink when the pen is nib-up, then a drop in ambient air pressure will cause the air bubble above the ink to expand, pushing a significant amount of ink up and out of the pen. Not aerometric.

 

If you cut that PTFE tubing short, then you will only get this bad behaviour some of the time -- when you have a lot of ink in your pen, that is, enough ink so that the level of the ink reaches up to cover the tip of the breather tube when the pen is nib-up. But this won't happen, because you can't actually load much ink into an ink reservoir if the breather tube is short! So you threw the baby out with the bath water: you (partially) cured your flying-with-a-pen problem, but now your pen might as well just use some lame 0.5 ml cartridge converter. The "aerometric" design, with the metal breather tube, has a long breather tube, which reaches way back into the ink sac. So you can load in a large load of ink, but the breather tube's side piercing makes it: aerometric.

 

So, I submit that an aerometric pen is one with a long breather tube that has the "aerometric" hole pierced in its side to provide a side return path for expanding air trapped in the sac.

 

An "aerometric" Parker "51" without such a mechanism isn't aerometric. It's just a squeeze filler.

 

At least, that is the way it seems to me.

 

E. K.

[FarmBoy]

Note that pressure equalization can happen as long as there is not a liquid seal at the feed, hole or no hole.

Edited March 11, 2017 by FarmBoy

[ek-hornbeck]

Yes, they clog. And the clogging then cause corrosion of pen parts and especially of the sterling tube in a P51.

 

http://gregminuskin.com/?p=2426

 

Do you have any evidence of this?

 

The link you provided is not evidence. It supports a different claim: that at least one of the Noodler's inks can melt the soft, non-metallic material used to make the feed of some pens.

 

One, I am talking about nano-pigment inks, not whatever Noodler's ink is. I've never seen a statement by Tardif that Noodler's inks are nano-pigment based. He is always carefully vague about what his inks are, limiting himself to abstract descriptions that the ink goes through some kind of unspecified chemical change when it goes into the cellulose of the paper. Which doesn't sound like a nano-pigment ink at all. But who knows what Noodler's inks really do? I carefully left Noodler out of the list I provided for that exact reason.

 

Two, I am talking about stainless steel and silver, not hard rubber or plastic.

 

I'm not saying you are wrong. You may well be right. But I would like to know what your reason is for stating that nano-pigment inks can corrode steel and silver. Someone you respect told you this? You read it on FPN? You personally have disassembled a pen that you know for a fact only used a nano-pigment ink (not a Noodler's ink) and you saw, with your own eyes, corrosion? You ran an experiment and left a sacrificial breather tube immersed in a little vial of nano-pigment ink for a year? These are all reasons one might believe what you have stated, but they all carry different amounts of weight. So it would be really useful for me if you could say which one applies.

 

Especially since it seems to (amateur, non-expert, novice) me pretty unlikely that nano-pigment ink should be corrosive. The stuff is sold by major pen manufacturers: Sailor, Montblanc, and Platinum all sell nano-pigment ink under their label. At least three companies of which I know have gone to the trouble to obtain ISO certification for their nano-pigment inks: De Atramentis, Rohrer & Kligner, and Montblanc. Finally, there doesn't seem to be anything particularly corrosive in the basic idea of a nano-pigment ink.

 

So I would be very suprised if these inks are actually corrosive. Such a thing would be very, very interesting to discover. Which is why I am so interested in the support for your statement.

 

On the other hand, it would not be interesting at all to discover that some Noodler's inks are corrosive. That seems to be pretty well known.

 

E. K.